The properties of Na ion-dependent preferential binding, and the dissociation of activity transported sugars and amino acids by hamster intestinal microvillus filaments and the isolated binding protein(s) from this structure will be studied. The effects of Na ion depletion, substrate concentration, pH, incubation time, competitive inhibitors, and actively and nonactively transported sugars and amino acids on binding will be observed. In addition, the effects of cations, adenine, nucleotides, and ouabain on sugar and amino acid dissociation will be determined. (Na-K ions)-ATPase activity of microvillus filaments and the isolated sugar and amino acid binding protein(s) will be determined under the same conditions employed for the dissociation experiments. A study will be undertaken to examine the physical properties and chemical composition of the purified sugar and amino acid binding protein(s). These techniques for studying the mechanism of intestinal sugar and amino acid transport at the subcellular and molecular levels will be applied toward solving problems related to irregularities in the absorption of sugars and amino acids, in vitro, caused by diet and diabetes. BIBLIOGRAPHIC REFERENCES: Faust, R. G. and S. J. Shearin, "Molecular basis of intestinal active sugar and amino acid transport" Int'l. Cong. Physiol. Sci. 11, 1974. Faust, R. G., "The intestinal brush border as an organelle". In: Intestinal Absorption and Malabsorption. Ed. by T. Z. Csaky, pp 155-175, Raven Press, N. Y., 1975.